Toolbox — after a gap of 15 months

We just released version 0.0.99, and I realized that it’s been a while since I blogged about Toolbox. So it’s time to address that.

Rewritten in Go

About a year ago, Ondřej Míchal single-handedly rewrote Toolbox in Go, making it massively easier to work on the code compared to the previous POSIX shell implementation. Go comes with much nicer facilities for command line parsing, error handling, logging, parsing JSON, and in general is a lot more pleasant to program in. Plus all the container tools in the OCI ecosystem are written in Go anyway, so it was a natural fit.

Other than the obvious benefits of Go, the rewrite immediately fixed a few bugs that were inherently very cumbersome to fix in the POSIX shell implementation. Something as simple as offering a –version option, or avoiding duplicate entries when listing containers or images was surprisingly difficult to achieve in the past.

What’s more, we managed to pull this off by retaining full compatibility with the previous code. So users and distributors should have no hesitation to update.

Towards version 0.1.0

We have been very conservative about our versioning scheme so far due to the inherently prototype nature of Toolbox. All our release numbers have followed the 0.0.x format. We thought that the move to Go deserves at least a minor version bump, but we also wanted to give it some time to shake out any bugs that might have crept in; and implement the features and fix the bugs that have been on our short-term wish list before putting a 0.1.0 stamp on it.

Therefore, we started a series of 0.0.9x releases to work our way towards version 0.1.0. The first one was 0.0.90 which shipped the Go code in March 2020, and we are currently at 0.0.99. Suffice to say that we are very close to the objective.

Rootful Toolboxes

Sometimes a rootless OCI container just isn’t enough because it can’t do things that require privilege escalation beyond the user’s current user ID on the host. This means that various debugging tools, such as Nmap, don’t work.

Therefore, we added support for running toolbox as root in version 0.0.98.1. This should hopefully unlock various new use-cases that were so far not possible when running rootless.

When running as root, Toolbox cannot rely on things like the user’s session D-Bus instance or the XDG_RUNTIME_DIR environment variable, because sudo doesn’t create a full-fledged user session that offers them. This means that graphical applications can only work by connecting to a X11 server, but then again running graphical applications as root is never a good idea to begin with.

Red Hat Universal Base Image (or UBI)

We recently took the first step towards supporting operating system distributions other than Fedora as first class citizens. From version 0.0.99 onwards, Toolbox supports Red Hat Enterprise Linux hosts where it will create containers based on the Red Hat Universal Base Image by default.

On hosts that aren’t running RHEL, one can still create UBI containers as:
$ toolbox create --distro rhel --release 8.3


Read more

Those were some of the big things that have happened in Toolbox land since my last update. If you are interested in more details, then you can read Ondřej’s posts where he writes at length about the port to Go and the changes in each of the releases since then.